This invention relates to medical gas service outlets and adapters that are used to receive gas from such outlets for delivery of that gas to some end use.
Such outlets are quite common in hospital rooms where gas services such as oxygen, air, nitrous oxide as well as vacuum service can be provided. The user can conveniently plug in the various equipment that utilizes the particular service with a specially designed, keyed adapter that generally is connected to medical tubing for delivery to its end use device.
A typical example of such outlets can be seen in U.S. Pat. No. 3,563,267, C. S. Thompson and 4,190,075, J. P. Kayser. In particular, an adapter is shown and described in U.S. Pat. No. 2,905,487 of H. Schifter. In the Schifter patent, the adapter is inserted into the service outlet until it reaches its desired position where it is engaged and held in place by a hair pin shaped wire spring that straddles a cylindrical projection on the adapter and fits within flats cut into the projection. To remove the adapter, the cylindrical projection is rotated such that the flats are twisted away from the retaining wire spring and the wire spring legs are spread such that the spring legs are no longer seated within the flats. The adapter can thus be removed from the service outlet. Such adapters normally provide that the cylindrical projection is spring biased so that it snaps back to its original position once removal has been effected.
One difficulty with such adapters is in their manufacture and assembly. One type currently available, is similar to that shown in U.S. Pat. No. 2,905,487 and requires a number of components that must be individually assembled during manufacture. Thos components include a coiled wire spring that is fitted quite meticulously into the adapter during assembly and which creates the spring bias to return the cylindrical Projector to its original position when released by the user. Not only is the individual spring relatively expensive but it requires preloading by an assembler during assembly of an adapter to align and insert the spring. The overall schifter type of adapter also requires a plurality of parts that are costly in terms of both material and labor. Obviously, any cost in a product that is mass produced is not desirable if an alternative can be utilized having fewer parts and less tedious assembly.